Volcanoes

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Earth Science HS: Volcanoes

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Volcanoes

  1. 1. VOLCANOES
  2. 2. Launch Lab • Take one beaker (containing water and oil) and salt cup • Sprinkle salt into the beaker in one spot for five seconds • Observe 1.Which component of your model represents magma? 2.What happened to the oil before and after you added the salt? 3.What do you think causes “magma” (oil) to rise?
  3. 3. Volcanism • Movement of magma toward or onto the Earth’s surface ***magma is less dense than surface so it pushes its way up
  4. 4. Volcanoes • http://mass.pbslearningmedia.org/resource/i dptv11.sci.ess.earthsys.d4kvol/volcanoes/
  5. 5. Where they form…. 1. Convergent Boundaries 2. Divergent Boundaries
  6. 6. Where they form…. 3. Hot Spots
  7. 7. Hot Spots • Magma comes to the surface from within a plate (not at a boundary) that continues to move over spot producing lava Hawaiian Islands Galapagos Islands
  8. 8. How Hawaii was formed …. • http://mass.pbslearningmedia.org/resource/nat08.
  9. 9. All three types
  10. 10. Parts of a Volcano • Volcanic cones – piles of volcanic material built up around vent • What you see on the surface and call volcanoes
  11. 11. Parts of a Volcano • Lava = Magma on earth’s surface • Tephra = fragments of volcanic rock blown into atmosphere • Conduit = tube-like structure lava travels through to create a vent
  12. 12. Parts of a Volcano •Vent = opening in earth’s surface where magma flows through •Fissure = linear crack which lava flows out
  13. 13. vent fissure
  14. 14. Anatomy of a Volcano
  15. 15. Crater vs. Caldera • Crater = bowl-shaped depression at top of vent; formed when material is blown from vent during explosions • Caldera = large basin shaped depressions formed either by explosions or cones collapsing
  16. 16. Types of Volcanoes • http://www.pbs.org/wgbh/nova/earth/meet-volcan
  17. 17. Three types of Cones (volcanoes) 1. Shield cone - largest type -quiet eruptions where lava slowly flows out - basaltic lava
  18. 18. Basaltic lava flows into ocean • http://mass.pbslearningmedia.org/resource/b f10.sci.ps.earth.stormsea/stormy-seas/
  19. 19. Basaltic Lava On land: pahoehoe – thin lava with wrinkled hardened texture aa – sharp chunks of lava that form when lava continues to flow underneath cooling lava
  20. 20. Basaltic Lava In Ocean: pillow lava – shape of cooled lava that escapes fissures of midocean ridges
  21. 21. Three types of Cones (volcanoes) cont… 2. Cinder cone - made up of solid fragments - steep slopes rarely high very explosive - Smallest kind - Forms on edge of Other cones
  22. 22. Three types of Cones (volcanoes) cont… 3. Composite Cone (stratovolcanoes) - alternating hardened lava and tephra - lava flows clog vent and cause eruption of tephra then lava flows cause clog again - develop into high volcanic mountains - Mt. St. Helen’s, Mt. Pinatubo, Mt. Rainier
  23. 23. Mt. St. Helens
  24. 24. Mt. St. Helens • http://mass.pbslearningmedia.org/resource/i dptv11.sci.ess.earthsys.d4kmsh/mount-sthelens/
  25. 25. Other hazards from eruptions
  26. 26. Volcanic Rock Fragments • Volcanic bombs – rounded or spindle shape tephra particles caused by lava spinning through air • Volcanic blocks – largest kind of tephra – some as big as houses
  27. 27. Lahars • Lahars - mudflows made of pyroclastic material, mud, and water – Very destructive – Dense as concrete
  28. 28. Mt. Pinatubo • http://mass.pbslearningmedia.org/resource/e ss05.sci.ess.earthsys.lahar/mount-pinatubothe-aftermath-of-a-volcanic-eruption/
  29. 29. Pyroclastic flows • Pyroclastic flows - Rapidly moving clouds of tephra mixed with hot, suffocating gases (sulfuric acid)
  30. 30. Predicting Volcanoes 1. Seismographs 2. measuring gases given off – sulfur dioxide (SO2) 3. study past history of volcanoes 4. bulging of volcanic slopes • http://mass.pbslearningmedia.org/resource/ess05.sci.ess.earth sys.pinatubo/mount-pinatubo-predicting-a-volcanic-eruption/
  31. 31. Extraterrestrial Volcanism Many planets & moons in the solar system were and are volcanically active
  32. 32. Extraterrestrial Volcanism The Moon Covered by Basaltic flows; no longer active; however, no evidence of plate tectonic activity
  33. 33. Extraterrestrial Volcanism Mars Numerous volcanoes & features; biggest one is a shield volcano called Olympus Mons
  34. 34. Extraterrestrial Volcanism IO Moon on Jupiter; shows 9 active volcanoes erupting on Io http://mass.pbslearningmedia.org/ resource/flbe12.sci.ess.eiu.iovolca no/io-and-volcanism/
  35. 35. Yellowstone • http://mass.pbslearningmedia.org/resource/n vdv.sci.earth.yellowvolc-1/volcanism-atyellowstone/

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